Value of rectal ultrasound in predicting staging and outcome in patients with rectal adenocarcinoma.

Purpose: Transrectal ultrasonography is considered the best method to stage rectal cancer, and thus the need for preoperative radiotherapy. This retrospective study was designed to determine the prognostic value of uTN classification on survival of patients treated by preoperative radiotherapy and surgery.

Methods: A total of 218 patients with proven rectal adenocarcinoma were staged by transrectal ultrasonography before treatment. Transrectal ultrasonography reports were reviewed for TN classification, quality of examinations, and downstaging (pT < uT).

Results: Transrectal ultrasonography stages were as follows: uT1, n = 2; uT2, n = 61; uT3, n = 145; uT4, n = 10; uN0, n = 94; uN+, n = 124. After radiotherapy, based on operative specimen, lesions were staged as pT0, n = 27; pT1, n = 20; pT2, n = 60; pT3/4, n = 111; pN0, n = 160; pN+, n = 58; pM+, n = 10. Downstaging (measured as a reduction in TN level determined by transrectal ultrasonography and pathology of resected specimen) occurred in 42.6 percent for T and 38.1 percent for N. Five-year overall and disease-free survivals were 71.3 and 62.7 percent, respectively (median follow-up, 62 months). In univariate or multivariate analysis including parameters available before treatment, uT and age but not uN were statistically significant prognosis factor for overall survival. Patients with TN downstaging had significantly better overall survival. In multivariate analysis, including all parameters, only age, gender, pT, and pN+ status predicted poor outcome.

Conclusions: In patients with rectal adenocarcinoma treated by preoperative radiotherapy, uT classification determined by transrectal ultrasonography before radiotherapy, pT and pN classification determined after radiotherapy, and tumor downstaging were predictors of survival contrary to uN. Only pTN classification, age, and gender were independent predictors in multivariate analysis.